Wide Range Of Structural Types Research Articles

Utilization of Natural Products for Treatment of Blood Diseases

This chapter presents an introduction to several diseases of the blood including infectious mononucleosis, leukemia, thrombosis and coagulation, bone marrow disorders, malaria, and anemia. In addition a survey of the recent literature is presented relative to natural products that have been utilized for the treatment of these diseases. The natural products that are reported represent a wide range of structural types and present interesting mechanisms of action. Thus the possibility exists that new drugs may be developed from these natural products which are more effective than those currently on the market.

Lessons from the Kobe earthquake

Abstract The Kobe earthquake is considered to be one of the most devastating and costly natural disasters in recent history considering the number of buildings destroyed, the number of people killed and injured, the size of the affected area, and the extent and severity of damage to a wide range of structural types. As a result, important questions have been raised about earthquake preparedness, disaster response, seismic design and codes of practice, and upgrading of earthquake-resistant structures. This paper presents an overview of this earthquake, investigates the extent and types of damage caused, studies the factors behind each type of damage, and highlights important lessons learnt from this earthquake. Protective measures and future research that should be undertaken in Japan, and all countries that are at seismic risk, are recommended in order to reduce damage and casualties in future seismic events.

The location of transition states: A comparison of Cartesian, Z-matrix, and natural internal coordinates

A comparison is made between geometry optimization in Cartesian coordinates, in Z-matrix coordinates, and in natural internal coordinates for the location of transition states. In contrast to the situation with minima, where all three coordinate systems are of comparable efficiency if a reliable estimate of the Hessian matrix is available at the starting geometry, results for 25 different transition states covering a wide range of structural types demonstrate that in practice Z-matrix coordinates are generally superior. For Cartesian coordinates, the commonly used Hessian update schemes are unable to guarantee preservation of the necessary transition state eigenvalue structure, while current algorithms for generating natural internal coordinates may have difficulty handling the distorted geometries associated with transition states. The widely used Eigenvector Following (EF) algorithm is shown to be extremely efficient for optimizing transition states. © 1996 by John Wiley & Sons, Inc.

Screening assay for dioxin-like compounds based on competitive binding to the murine hepatic Ah receptor. 1. Assay development

PCDDs, PCDFs, and related analytes were assayed by binding the analytes competitively with fixed aliquots of radiolabeled 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and C57BL/6 mouse hepatic Ah receptor. Additive binding to the receptor was observed for a wide range of structural types of chlorinated aromatic compounds. The results of the assays were expressed as TCDD equivalents, i.e., the concentration of unlabeled TCDD that would give the same assay as the mixture of analytes. The detection limit was approximately 100 pg of TCDD equivalent when the reference radioligand was [ 3 H] TCDD. The assay does not require prior knowledge of the identities of the components of the mixture and is intended for use as a prescreening tool ratherthan as a replacement for the conventional analysis by GC/MS.

A generic model for building design

The design of building structures has benefited considerably through computer automation, but further developments in this field are still required. This paper presenis a generic approach to computer automation of the detailed design of building structures. Because of its high level of abstraction, the resulting model is applicable to a wide range of structure types. Other advantages include the use of a consistent data model for software design and implementation, abstract data types for the representation of engineering data, the ability to represent heuristic knowledge, and the ability to evaluate design results in an intelligent manner.

Atomic force microscopy studies of layer silicate minerals

The surfaces of silicate minerals are important in controlling a number of geochemical phenomena from chemical weathering, to the transport of pollutants in solution. The atomic force microscope (AFM) has proven invaluable for obtaining atomic resolution images of the surface topology and structure of a wide variety of minerals. While the physical basis for the sample—tip interactions responsible for the images remains poorly understood, comparison of AFM images with the calculated bulk mineral structures, provides clear evidence that the AFM is truely capable of resolving structural features on the atomic scale. The phyllosilicate or layered silicate minerals are particularly suited to study by atomic force microscopy because of their perfect {001} cleavage, wide range of structure types and variety of surface properties. Atomic resolution images have been obtained on lizardite, chlorite, apophyllite and muscovite. The AFM resolves the Ångstrom-scale surface structure of these minerals and is able to clearly elucidate the different structural layers. These studies have been able to observe surface relaxation effects on the surface of chlorite, as well as the progressive amorphization (through ion beam damage) of the muscovite surface. Further, studies in solution are able to image the equilibrated near surface structure providing fresh insight into the nature of the mineral—water interface.

Peripheral Considerations: Defining the Spatial and Physical Correlates of Storage Behavior in Hohokam Structures

ABSTRACTA new approach for investigating the use and organization of intramural space provides insights into the nature and distribution of storage in Hohokam structures. Consideration of the spatial and physical manifestations of storage behavior provides evidence that specific areas in structures were consistently set aside for storage. Use-areas located in the periphery of structures and other locations reveal patterned evidence of storage in a wide range of structure types. Recognition of particular use-area types, including the peripheral zone, provides alternatives to traditional function-based classifications for the analysis of structures.

Bond valence sum analysis of metal-ligand bond lengths in metalloenzymes and model complexes

Bond valence sums (BVS's) have been calculated for a series of model complexes for important metalloenzymes. Values calculated from crystallographic distances predict the correct oxidation state of the metal center in a wide range of structural types. Many of the selected complexes have previously been studied by X-ray absorption spectroscopy, and first-shell metal-ligand bond distances have been determined by analysis of extended X-ray absorption fine structure (EXAFS)

Iminophosphanes: Unconventional Compounds of Main Group Elements

AbstractThe large number of known stable compounds in which phosphorus has a low coordination number makes it clear that such compounds can no longer be regarded as “exotic” in main group chemistry. While the rich chemistry of PC multiply bonded systems makes clear their affinity to their organic congeners, iminophosphanes in particular are also of increasing importance. The linkage of a phosphinidine fragment with an imine fragment via a multiple bond gives rise to a class of compounds with an unusually wide range of structural types. This in turn leads to a broad spectrum of chemical behavior which makes iminophosphanes extremely useful synthetic building blocks in organoelement chemistry.

Interactions of alkaloids with galeal chemosensory cells of colorado potato beetle

The galeal chemosensory system of the adult Colorado potato beetle was used as a model to study the effects of alkaloids on insect gustation. Nine alkaloids, representing a wide range of structural types, were used. Their ability to stimulate chemosensory cells when presented in isolation and their ability to interfere with normal chemosensory processes were emphasized. None of the alkaloids stimulated chemosensory cells in a dose-dependent manner, although a few stimulated low-level activity from some cells. There was no evidence for a general "deterrent receptor" in these beetles. Some of the alkaloids had a marked inhibitory effect on normal chemosensory responses. Tomatine, solanine, papaverine, and sparteine significantly inhibited responses to amino acids (represented by GABA) while quinine and papaverine inhibited responses to sucrose. An attempt was made to correlate neurophysiological action of some alkaloids with their effects on feeding behavior. It was clear from this correlation that even a dramatic inhibition of sensory input by an alkaloid does not necessarily lead to measurable effects on behavior. The results are discussed in the context of current theories on the mode of action of alkaloids and other secondary plant compounds which may be involved in host recognition by phytophagous insects.

Reactions of lead tetraacetate. II. Formation of carbamic acid esters from primary carboxamides

Treatment of primary carboxamides with lead tetraacetate in benzene-alcohol mixtures or neat alcohol affords a convenient, flexible, and efficient method for the preparation of N-substituted carbamic acid esters. The reaction is applicable to amides and alcohols of a wide range of structural types including compounds containing oleflnic, ester, aromatic, and other reactive functions. The reaction mechanism appears to involve intermediate formation of isocyanates.